electron/shell/common/asar/asar_util.cc
Charles Kerr 987300c97a
refactor: omit redundant map searches (#19929)
* refactor: don't walk maps twice to remove elements

* refactor: don't walk maps twice to read elements

* refactor: don't walk maps twice to insert elements

* refactor: don't walk map 3x on UvTaskRunner timeout

* refactor: more don't-walk-maps-twice cleanup

* fixup! refactor: don't walk maps twice to insert elements

* refactor: don't walk containers twice when erasing

* refactor: omit excess lookups in RemoteObjectFreer
2019-08-28 09:39:21 -05:00

108 lines
3 KiB
C++

// Copyright (c) 2015 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "shell/common/asar/asar_util.h"
#include <map>
#include <string>
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/lazy_instance.h"
#include "base/stl_util.h"
#include "base/threading/thread_local.h"
#include "shell/common/asar/archive.h"
namespace asar {
namespace {
// The global instance of ArchiveMap, will be destroyed on exit.
typedef std::map<base::FilePath, std::shared_ptr<Archive>> ArchiveMap;
base::LazyInstance<base::ThreadLocalPointer<ArchiveMap>>::Leaky
g_archive_map_tls = LAZY_INSTANCE_INITIALIZER;
const base::FilePath::CharType kAsarExtension[] = FILE_PATH_LITERAL(".asar");
} // namespace
std::shared_ptr<Archive> GetOrCreateAsarArchive(const base::FilePath& path) {
if (!g_archive_map_tls.Pointer()->Get())
g_archive_map_tls.Pointer()->Set(new ArchiveMap);
ArchiveMap& map = *g_archive_map_tls.Pointer()->Get();
// if we have it, return it
const auto lower = map.lower_bound(path);
if (lower != std::end(map) && !map.key_comp()(path, lower->first))
return lower->second;
// if we can create it, return it
auto archive = std::make_shared<Archive>(path);
if (archive->Init()) {
base::TryEmplace(map, lower, path, archive);
return archive;
}
// didn't have it, couldn't create it
return nullptr;
}
void ClearArchives() {
if (g_archive_map_tls.Pointer()->Get())
delete g_archive_map_tls.Pointer()->Get();
}
bool GetAsarArchivePath(const base::FilePath& full_path,
base::FilePath* asar_path,
base::FilePath* relative_path) {
base::FilePath iter = full_path;
while (true) {
base::FilePath dirname = iter.DirName();
if (iter.MatchesExtension(kAsarExtension))
break;
else if (iter == dirname)
return false;
iter = dirname;
}
base::FilePath tail;
if (!iter.AppendRelativePath(full_path, &tail))
return false;
*asar_path = iter;
*relative_path = tail;
return true;
}
bool ReadFileToString(const base::FilePath& path, std::string* contents) {
base::FilePath asar_path, relative_path;
if (!GetAsarArchivePath(path, &asar_path, &relative_path))
return base::ReadFileToString(path, contents);
std::shared_ptr<Archive> archive = GetOrCreateAsarArchive(asar_path);
if (!archive)
return false;
Archive::FileInfo info;
if (!archive->GetFileInfo(relative_path, &info))
return false;
if (info.unpacked) {
base::FilePath real_path;
// For unpacked file it will return the real path instead of doing the copy.
archive->CopyFileOut(relative_path, &real_path);
return base::ReadFileToString(real_path, contents);
}
base::File src(asar_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
if (!src.IsValid())
return false;
contents->resize(info.size);
return static_cast<int>(info.size) ==
src.Read(info.offset, const_cast<char*>(contents->data()),
contents->size());
}
} // namespace asar